The present invention relates generally to a fault detection system and method for steer-by-wire systems and more particularly relates to robust model-based fault detection system and method for steer-by-wire systems.
Steer-by-wire systems replace the mechanical linkage between a steering wheel and road wheels of a vehicle with electrical connections based on electrical actuation system including electric motor actuators, motor drivers, sensors, microprocessors, and other electrical and mechanical components. This allows the vehicle road wheels and steering wheel to be controlled by using electrical signals based on the electrical actuation motion system.
Due to the criticality of steering functionality, it is important for steer-by-wire system to provide fault detection function such that safe operation of vehicle can be maintained for possible faults which may occur in any component of a steer-by-wire system including sensors, actuators, and other electro-mechanical components. For instance, the fault should be detected and isolated to maintain the nominal direction control for the vehicle when a bias of the road wheel angle sensor occurs during normal operation of the steer-by-wire system.
Redundancy is needed to detect faults of systems and components. Redundancy is used to make consistency checks between related variables. A common redundancy for some components is hardware redundancy by using extra hardware. For example, a sensor is duplicated or triplicated and fault decision can be made to compare signal levels of sensors. For safe operation of the steer-by-wire control system, hardware redundancy being reliable and high performance for critical components should be implemented. However, redundancy is limited by weight, package, extra cost, space, consuming, and similar installation environment for the hardware.